IEstimator<ITransformer> dataPrepEstimator = 
mlContext.Transforms.Text.FeaturizeText("TextFeatures", "Name")
.Append(mlContext.Transforms.Concatenate("Features", features))
.AppendCacheCheckpoint(mlContext);

// features = {a, b, c, TextFeatures}

IEstimator<ITransformer> dataPrepEstimator = 
mlContext.Transforms.Text.FeaturizeText("TextFeatures", "Name")
.Append(mlContext.Transforms.Concatenate("Features", features))
.AppendCacheCheckpoint(mlContext);

// features = {a, b, c, TextFeatures}